Endovascular aneurysm repair (EVAR) has rapidly expanded since its introduction in the early 1990s. Early experiences were understandably associated with relatively high rates of complications including conversion to open repair. Soon, perioperative morbidity and mortality results improved but these concerns were replaced by questions over the long-term effectiveness of the endovascular method highlighted by the increasing numbers of secondary interventions and even reports of aneurysm rupture. A better understanding of the behaviour of stent-grafts in the aorta and the response of aortic aneurysms to endovascular repair has been forged by observations both in vitro and in vivo. It was only relatively recently that terms such as migration and endoleak were coined. Only now that we are beginning to fully understand the causes and consequences of such problems can further developments be made. The following paper outlines some of the concepts and discusses the controversies and challenges facing clinicians involved in endovascular aneurysm surgery today.